目標是解決最大的 GC pause 來源：
As of Go 1.7, the one remaining source of unbounded and potentially non-trivial stop-the-world (STW) time is stack re-scanning.
然後拿新的解法來戰，目前初步的測試看起來可以降到 50µs (== 0.05ms)：
We propose to eliminate the need for stack re-scanning by switching to a hybrid write barrier that combines a Yuasa-style deletion write barrier [Yuasa ’90] and a Dijkstra-style insertion write barrier [Dijkstra ’78]. Preliminary experiments show that this can reduce worst-case STW time to under 50µs, and this approach may make it practical to eliminate STW mark termination altogether.
在「 runtime: eliminate stack rescanning · Issue #17503 · golang/go 」這邊可以看到進度，現在已經在 master branch 上了，看起來會在 1.9 的時候被放出來… 不過 worst case 的時間上修了 XDDD
The high level summary is that this reduces worst-case STW time to about 100 µs and typical 95%ile STW time to 50 µs (assuming, of course, that the OS doesn’t get in the way and that the system isn’t otherwise overloaded).
但看起來應該還是很大的效能改善，尤其是 CPU bound 的應用？